1. Field of the Invention
The invention relates to a valve arrangement for guiding a liquid against a gas pressure gradient.
2. Discussion of Background Information
Situations are known in practice where a liquid has to be guided against a gas flow or a gas counterpressure. In the field of internal combustion engines, in particular in the field of automotive engineering, a situation like this exists, e.g., in the area of crankcase ventilation: gas that flows out of the crankcase through a liquid-vapor separator is guided into the suction passage of the internal combustion engine. The pressure prevailing in the suction passage or in the flow direction behind the liquid-vapor separator is lower than the pressure prevailing in the crankcase. However, the oil separated in the liquid-vapor separator is intended to drain into the crankcase.
It is known from DE 296 05 425 to provide a leaf spring valve for the separated oil, which valve is arranged in an oil collecting tank. As soon as separated oil accumulates in this collecting tank and reaches a preset hydrostatic level, the leaf spring opens due to the hydrostatic pressure and the oil can drain out. However, as soon as gas flows through the opening, a pressure difference forms again at the leaf spring and causes the flow check valve formed by the leaf spring to close again automatically. It is a disadvantage in this technical solution on the one hand that a high manufacturing accuracy in the area of the leaf spring is necessary in order to ensure uniform valve properties in series production, moreover, a certain minimum construction height of the oil collection chamber is necessary to achieve the desired hydrostatic pressure, which is a drawback in view of the frequently cramped installation conditions, e.g., in the engine compartment of a motor vehicle. In different engine concepts the pressure difference at the separator is so great that draining off the separated oil is possible only when the engine is at rest. The dimensions of the oil collection chamber then have to be so large that the entire oil amount collected until the engine is switched off can be stored.